A traditional circular saw (i.e. miter saw) usually has a trough formed on a worktable adapted for allowing the saw blade to pass partially through such that cuts at various angles can be made. In order to provide support to a workpiece of small size on the worktable, and to prevent sawdust or debris from falling into the trough from kickback due to rotation of the saw blade, the trough is usually covered by a table insert made of soft material. The table insert has a cutting slot formed thereon for allowing the saw blade to pass therethrough. However, when a cutting operation is performed, debris or wood chips of smaller size may still fall into the trough through the cutting slot. If the trough is not cleaned immediately, the clogged debris and wood chips may still kickback from the trough due to rotation of the saw blade and may lead to injury to the user.
As shown in FIG. 1, the conventional table insert 4 for a circular saw is threadedly secured to the worktable through a plurality of bolts. When cleaning the trough 3, the user must loosen all the bolts to remove the table insert. When the debris/chips are removed, the user once again needs to tighten all the bolts to secure the table insert 4 to the worktable. Therefore, it can be concluded that the conventional table insert 4 for a circular saw is inconvenient to install, which consequently impacts the cutting efficiency.